Belt grinder



`lune 9, 1964 L 1 HINE 3,136,096

BELT GRINDER Filed Sept. 27, 1960 4 Sheets-Sheet 1 INV EN TOR.

L. J. HINE BELT GRINDER June 9, 1964 4 Sheecs-Sheei'l 2 Filed sept. 27, 1960 4 Sheets-Sheet 3 L. J. HINE BELT GRINDER June 9, 1964 Filed Sept. 2'?, 1960 L. J. HlNE BELT GRINDER June 9, 1964 4 Sheets-Sheet 4 Filed Sept. 27, 1960 INV EN TOR. 0a/.s .JI rf/ME United States Patent O 3,136,096 BELT GRINDER n Louis J. Hine, Gloversville, N.Y., assignor, by direct and mesne assignments, of one-half to Curtin-Hebert Company, Inc., Gloversville, N.Y., a corporation of New York, and one-half to Norton Company, Troy,

N.Y., a corporation of Massachusetts Filed Sept. 27, 196i), Ser. No. 58,829 36 Claims. (Cl. 51-142) This invention relates to grinding machines, and more particularly to such machine of the type using an abrasive belt. The machine may be wide, as for accurately finishing sheet material.

Some belt grinder contact rolls are cantilevered from one end, using a long, rigid bearing on that end in order to support the overhung roll. This is done in order to leave the other end free or open for installing the abrasive belt. In some machines the contact roll is supported by bearings on both ends, but the bearing at one end is removable. This still requires a long, rigid bearing at the other end, in order to support the contact roll while a belt is being changed, and heavy framing is needed to support the long bearing. It also presents a problem of bearing alignment, because three-bearing points must be kept in perfect alignment. As the machine Wears it becomes increasingly diicult to maintain this alignment.

The primary object of the invention is to overcome the foregoing difficulties and to generally improve belt grinders.

Another object of the present invention is to facilitate and speed the changing of the abrasive belt in a belt grinder. This is done by providing a tiltable or self-aligning bearing at one end, and extending the shaft of the contact roll well beyond that bearing. At the other end the second main bearing is provided with quick release clamping means, and on release the contact roll may be tilted, preferably by means of a power actuator operating on the extended end of the contact roll shaft. The contact roll is preferably tilted rearward as Well as upward, thereby moving it away from the adjacent pressure roll, and toward the remote idler roll, all of which facilitates installation of a new belt. In accordance with an ancillary feature and object of the invention, the main power drive of the contact roll is so arranged as not to restrain or interfere with the tilting of the contact roll. A specific means for tilting the Contact roll is described herein, but other means is described and the broad concept is claimed in a co-pending application of Dirck J. Olton and William A. Fazioli, Serial No. 68,477, filed November 10, 1960.

A further object of the present invention is to provide for a finer surface finish of the product, and longer life of the abrasive, by oscillating the belt, and more specifically the contact roll, a short distance in axial direction. This is not random, but is done under power drive, as by means of an eccentric operatively connected to the contact roll shaft.

Another object of the invention is to provide such oscillation mechanism which does not interfere with tilting of the contact roll shaft as above described. For this purpose the said mechanism is so mounted that it tilts with the contact roll shaft, as by means of a support bracket secured to the self-aligning bearing.

A still further object is to so mount the idler roll as to automatically tension the abrasive belt, and to so pivotally mount the idler roll that it may be used with belt tracking mechanism to prevent excessive displacement of the belt in lateral direction. The tracking mechanism and the overhung mounting of the idler roll are located on the same side of the machine as the tilting mechanism, so that the idler roll as well as the contact roll are open at 3,135,095 Patented June 9, 1964 ice the opposite side of the machine for installation of an abrasive belt.

Still another object of the invention is to afford axial oscillation of the idler roll, so that it may follow the driven oscillation of the contact roll. An ancillary object is to provide a compact and simplified means for this purpose which does not interfere with thebelt tensioning and yautomatic tracking movements of the idler roll, nor with the installation of a new belt.

To accomplish the foregoing general objects, and other more specific objects which will hereinafter appear, my invention resides in the belt grinder elements and their relation one to another, as are hereinafter more particularly described in the following specification.

The specification is accompanied by drawings in which:

FIG. 1 is an end elevation of a belt grinder embodying features of my invention;

FIG. 2 is a section drawn to greatly enlarged scale through one of the bearings of the idler roll;

FIG. 3 is a plan View showing the relation between the contact roll and the idler roll, and simpliied by the omission of other mechanism in front of and at the ends of the contact roll;

FIG. 4 is ra fragmentary end view of the contact roll, drawn to larger scale than FIG. 1, and explanatory of the mechanism controlling the contact roll;

FIG. 5 is a detail showing a paddle-controlled switch forming a part of the tracking mechanism;

FIG. 6 is a plan view of the contact roll;

FIG. 7 is explanatory of the tracking mechanism;

FIG. 8 is a fragmentary end view of the releasable bearing of the contact roll;

FIG. 9 is a longitudinal section taken in elevation through the contact roll, looking from the rear toward the front, and explanatory of the tilting and oscillating mechanism; and

FIG. 10 shows retractable gibs used to lock the releasable bearing in position.

Referring to the drawing, and more particularly to FIG. 9, the endmost portions of the main roll or contact roll are shown at 12. The roll either is formed integrally with or more usually is carried by a shaft 14. There is a tiltable bearing 16 lixedly mounted at one end of the roll 12, as on machine frame 18. In the preferred form the tiltable bearing is a self-aligning bearing, that is, the outer race 20 is carried by a ring 22 having a spherical surface 24 which mates with a concave spherical surface on the inside of bearing housing 26.

There is also a bearing 28 at the other end of the roll 12, together with a quickly releasable means, generally designated 30, to lock the said bearing to its support or frame 32.

The shaft 14 projects for a substantial distance outside the shaft bearing 16, and a generally upright actuator 34 is connected to a bearing 36 on the projecting end of the shaft 14. Thus on releasing the releasable bearing 28, the actuator 34 may pull the bearing 36 downward, thereby tilting the free end of the shaft and the contact roll upward, as indicated in broken lines at 12', 14', and 28. This facilitates changing the abrasive belt on the contact roll, that is, the removal of a worn belt and the installation of a new one.

In FIG. 9 attention is called to the fact that the main driving pulley 38 is secured to shaft 14 outside the shaft bearing 16. It is driven by a belt 40 which is generally upright and which extends downward, because the driving motor is in the base of the machine, as is best shown in FIG. 1, in which motor 42 drives the contact roll 12 through belt 40 and pulley 38. The motor is mounted on a platform 44 which is pivoted at 46, and which may be adjusted by means of screws 48 and nuts 50 to vary belt tension.

La Reverting to FIG. 9, it will be seen that with this arrangement the belt 413 is slackened slightly when the contact roll is tilted upward, and thus the belt in no way interferes withthe desired tilting action.

' The releasable bearing 28 must be accurately positioned and iirrnly locked, and yet it is quickly releasable. Referring to FIG. 8, the bearing housing 2S is cut away at 52 and has sloping or dovetail faces 54. The frame 32 of the machine is provided with ways or guides S6 and 58, and these have mating sloping faces. Longitudinally slidable gibs are provided at 6d and 62 (FIGS. 8 and 10), and it will be evident that when these are in position, the bearing is held against upward movement. When they are pulled Vout of position,'the bearingis freed for upward movement. For a tight iit a wedging action is desired. However, to definitely and accurately x the location of the bearing, one gib, in this case the forward gib 6l), is made straight or has parallel sides, while the other, in this case the rear gib 62, is tapered or wedge shaped. f

`Referring'to FIGS.. 6 and 9, the gibs are moved longitudinally by means of clamps 64, connected to the gibs by rods 66, The clamps 64 are secured on a bracket or frame extension 68 secured to the main frame 32 by supports 70. The clamps need not be described in detail, being a commercially available product. The particular clamps here shown are the model P & P-SO made by Lapeer Manufacturing Company, of Lapeer, Michigan. They provide a self-locking or toggle leverage (not shown) such that a force of 800 lbs. is provided. When the clamp levers '72 (FIG. 9) are turned from the broken line posi-V tion 72 to the solid line position 72, the gibs are forced homeY and locked in home position.

FIG. l shows how the forward gib 6l) has parallel sides and therefore' serves to determine the seating or position of the bearing housing 38, while the rear gib 62 is tapered. The rear guide or rail 58 is either matingly tapered, or is secured on the machine frame 32 at a mating angle.

In order to limit the necessary travel of the gibs, they maybe cut away or notched, as indicated at '74. The bearing housing may be similarly notched, with the result that a limited travel of the gibs brings the inner end portions of the gibs to thenotch region, and brings the outer end portions outside the bearing housing, thusfreeing the bearing for upward movement, much as though the gib had been pulled outward for its entire length, in-

stead of only a fraction of its length as here required.V

It will be understood that the wedging action of the gibs is two directional, that is, the gib 62 wedges the bearing both horizontally and vertically, and the horizontal movement itself causes a vertical wedging action at the straight gib 60, with the net effect that the bearing is securely wedged in position both horizontally and vertically.

FIG. 8 is a view looking from the direction of the clamps, but in the clamps have been omitted in order to better show the gibs. It is as though a section were taken between the gibs and the clamps, except that the clamp supports 68 and 70 are shown.

Referring now to FIG. 1 of the drawing, the contact roll 12 carries an abrasive belt Si), and this cooperates with an accurately adjustable presure roll 82 disposed immediately in front ofV the contact roll 12. We deal here with a machine which may be large in dimension, but which is intended for precision work on ilexible sheets. The material may be ground to a thickness within a tolerance of say one thousandth of an inch. f For this purpose the pressure roll 82 is securely mounted in large bearings which are accurately adjustable in horizontal direction by means of micrometric screw adjustments. In the case her shown there is a micrometer handle S4 at each end of the pressure roll with scales to 0.001 inch, for accurate adjustment of the same.

For many purposes the pressure roll is close to the abrasive belt Su because the sheet material being operated on is very thin. The material may be fed along a work table 86 and passes between a pinch roll 88 and the pressure roll 82. Either (or both) of the rolls 82 and 88 is driven to feed the work slowly in front of the high speed belt. In the present case roll 82 is driven and roll 88 idles. Its exact position may be adjusted by means of pressure screws 9G and'stop screws 92 located at the ends of table 86 outside the width of the material being handled.

The far end of belt is supported on a roll 94. For convenience and-brevity this is called an idler roll, because it is not driven, and in that sense idles. However, it

also acts as a tensioning roll which keeps the belt taut,

and its further acts as a tracking roll which is adjustable to keep the belt from creeping toward one side or the other beyond a desired limit. In other words, it controls and limits the maximum lateral displacement of the belt. The main actuator 34, which tilts the contact roll 12, is here illustrated as an air cylinder, and while generally upright, it slopes somewhat. More specifically, the lower end, which is pivotally secured at 96, is displaced forwardly so that the piston rod 98 slopes rearwardly.

Because of the slope of the actuator 34, the freed end of the contact roll is moved rearward as well as upward, and therefore away from the closely adjacent pressure roll S2, and toward the idler roll 94. This obviously facilitates changing the abrasive belt, because the rearward tilt increases the space between contact roll 12 and presure roll 82., and at the same time decreases the spacing between the rolls 12 and 94 over which the new belt must be installed.

VReferring now to FIG. 4, the piston rod 98 of actuator 34 isr secured to a yoke 101B which straddles a bearing housing 102. The yoke is pivotally connected to the bearing housing on a diameter of the bearing, as indicated in broken lines by pivot pins 194. The mounting of the actuatory at its lower end is also pivotal, as indicated at 96. This takes care of angularity, and makes it possible for the assemblyV of piston rod 98 and its yoke 160 to be a rigid one.

Referring now to FIG. 9, the bearing housing 102 encloses a ball bearing 36 which eliminates friction. Moreover, the bearing V36 is preferably a thrust type of ball bearing, for a reason next explained.

The quality of the grinding action, that is, the smoothness of the product being treated, and also the life of the abrasive belt, are improved by a slight lateral or side-toside movement of the beltf This has long been recognized in the case of cylinder grinders. In the case of belt grinders it is customary to provide tracking means which limit the lateral travel or creep of the belt, and this results in some incidental sideward movement. However, such movement is random, occasional, and takes place at very low speed.

In the present case means are provided for power driven lateral motion, and in FIG. V9 it will be seen that an eccentric 104 is provided, this being driven at greatly reduced speed through a speed reducing gear box 106. The eccentric is connected by a link 108 through a pin 11@ to the bearing housing 102. This results in a small axial movement of the shaft 14, and with it the contact roll 12. To accommodate this movement the bearings 16 and 28 are cylindrical roller bearings which readily afford limited axial movement. In the present case the rollers are confined bythe inner race which is secured to the'shaft, but the outer race (eg. race 20 in bearing 16) is substantially wider than the length of the rollers, and it has a smooth cylindrical surface which thereby accommodates the axial movement of the rollers relative to the outer race.

In the particular mechanism here shown, the eccentric 164 is driven from the main shaft 14. More specilically the shaft carries a pulley 112 driving a belt 114 which drives a pulley 116 on input shaft 11S of the gear box 11116. This has appropriate reduction gearing leading to an output shaft 120 which carries a pulley 122 which is belted by a belt 124 to a pulley 126 on the shaft of eccentric 104.

These parts are all preferably carried by a bracket 128, which is secured to the tiltable or self-aligning bearing for movement therewith. In the present case the bracket terminates in a ring 130 which is bolted at 132 to the main bearing ring 22. The bearing structure also includes closure rings or plates 134 and 136, and these are preferably provided with lubrication and dust seals at 138 and 140. The dimensioning of the parts is such as not to interfere with the limited tilting action provided by the tilt actuator 34, al1 as previously described.

The mounting of the gear box and eccentric is also shown in FIGS. l, 4, and 6, in which the parts are similarly numbered.

No means is here provided to similarly reciprocate the idler roll 94 under power, but it is preferred to provide means to readily accommodate a corresponding or following movement of the idler roll. Referring to FIG. 3, the roll 94 is formed integrally with or is mounted on a shaft 142 carried in bearings generally designated 144. These are carried at the ends of a yoke 146.

One of the bearings 144 is shown in greater detail in FIG. 2, and both are constructed alike. Referring to FIG. 2, the main bearing housing 144 is supplemented by an auxiliary housing 146. The main bearing 148 takes the radial force, and is supplemented by a thrust bearing 150. This is a ball bearing designed to take axial thrust.

The main bearing 148 is a roller bearing having an outer race 152 which is cylindrical and substantially wider than the rollers 148, thereby accommodating the desired limited axial reciprocation of the idler roll 94. This reciprocation is limited by a compression spring 154 bearing against the thrust bearing 150. The tension of the compression spring is preferably made adjustable, in this case by means of a screw 156 and a lock nut 158. The bearing assembly is completed by a lubrication seal at 160.

It will be understood that by means of the screw adjustments the idler roll may be centered, and its ease Vof axial motion may be adjusted so that it will follow thev contact roll and abrasive belt. In practice the motion of the idler roll is made easy or encouraged for limited travel, and because of increasing spring force, is resisted beyond that amount which is kept within the limits of creep, as controlled by the regular belt tracking means next described.

Referring now to FIGS. l and 3 of the drawing, the yoke 146 is urged rearward in order to tension the belt 80. For this purpose resilient means may be provided, but in the present case I provide an air cylinder 162, the piston rod 164 of which is connected to the center of the yoke. The cylinder 162 is carn'ed at the inner end of on overhung beam 166 which is carried on the machine frame 168, that is, on the side of the machine having the xed (non-releasable) tiltable bearing 16. In addition the same side of the machine may be provided with tracking means 170 for detecting excessive lateral movement of the belt, and a means generally designated 172, which is automatically moved in response to the tracking means 170 for restoring proper belt position. This is done by tilting the yoke 146, and in the present case it is found most convenient to tilt the adjacent end 147 of the yoke upward or downward, that is, to tilt the yoke about the axis of the piston rod 164 (FIG. 3).

In FIGS. 1 and 7 there is a generally upright actuator or air cylinder 174 iixedly carried on anextension 176 (FIGS. l and 3) on the frame member 168 which carries the beam 166 for the belt tensioning cylinder 162. The actuator 174 is double ended, that is the piston is connected to opposed piston rods 180. These are 1ocated between arms 182 projecting from the end 147 of yoke 146.

The detection means 170 may be any one of a number of known types, such as those using a photoelectric cell,

the belt moves laterally far enough to uncover the jet,l

the paddle is tilted to the broken line position 184', thus changing the switch.

It will be understood that another companion paddle is continuously subjected to an air jet outside the belt, and when the belt creeps laterally in opposite direction until it interferes with the second air jet, the latter paddle rises and changes its switch condition. Thus, by spacing the two paddles and air jets apart, as shown in FIG. 3 at 170, an amount which limits the maximum permissible or desired displacement of the belt, the mercury switches may be used to control circuitry which appropriately moves the actuator 172.

Reverting to FIG. 7, the cylinder 174 receives air pressure under control of solenoid operated air valves and 192. Their solenoids 194 and 196 are controlled bythe mercury switches and air paddles previously mentioned. Thus the tilt of the yoke is controlled and is changed in proper direction to restore the belt when it creeps too far in one direction or the other. The tilt of the yoke is accommodated at the piston rod 164 of piston 162u (FIG. 3).

It will be understood that because the yoke 146 and cylinder 162 are disposed between the upper and lower spans of the belt, and because the tracking mechanism is mounted at that side of the machine which has the fixed (tiltable) bearing, there is no interference with sliding a new belt into position, and no disassembly of the machine is required other than release of the clamps 64 which hold the releasable bearing 28, and the admission of air to the actuator 34 which tilts the contact roll.

Referring to FIG. 9, the bearing 16 carries a greater load than the bearing 28. This is so because of the driving pulley and the shaft oscillating mechanism. The bear- 16 therefore may be augmented, and in one form of the invention the ring 134 has been extended toward the end of cylinder 12 far enough to receive another roller bearing, which then shares the load of bearing 20. Alternatively, the ring 136 could be extended to the right and tted with another bearing, or the rings 134 and 136 could both be extended and fitted with supplemental bearings. Another alternative is to replace the entire tiltable bearing 16 by another of the larger size designed to handle a greater load. The tiltable bearing 16 then is larger than the releasable bearing 28.

It is believed that the construction and method of use of my improved belt grinder, as well as the advantages thereof, will be apparent from the foregoing detailed description. The changing of belts is facilitated and expedited, even when dealing with a large heavy machine carrying a wide belt, and even when working on comparatively thin sheet materials requiring the pressure roll to be very close to the belt. This is of great advantage in saving not only labor time to change theA belt, but even more important, the downtime during which the costly machine is not being used for production purposes. formed under power. It is tilted not only upward so that the belt may be slid over the released bearing, but it is also tilted rearward, thereby moving it away from the pressure roll and toward the idler roll. The tilting action is not restrained by the main drive means for the contact roll. The abrasive belt during use is oscillated a limited amount under power drive, and the mechanism for this purpose does not interfere with tilting of the contact roll when changing the belt. The idler roll bearings are arranged to permit the idler roll to follow the oscillation of the contact roll.

I have illustrated the belt grinder arranged generally The tilting of the contact roll is per-V a', reactie horizontally. However, it should be understood that the` machine might be disposed at some other angle, for example generally vertical. In general, the actuator should move the free end of the contact roll away from the pressure roll and toward the idler roll. It should not be stopped by the main drive belt, and preferably releases the drive belt tension. Accordingly, in the claims such terms as uprigh `or in back of are to be construed in a relative, rather than in an absolute sense, to accomplish the described purpose. i

It will be understood that while I have shown and described my invention in a preferred form, changes may be made in the structure shown without departing from the scope of the invention, as sought tol be defined in the following claims.

I claim:

1. A belt grinder for accurately grinding wide sheet material to a desired thickness, said grinder comprising a contact roll, a tiltable bearing fixedly mounted at one end of said roll, a quickly releasable bearing at the other end of the roll, means including a movable wedge block and a lever for moving the same to lock or release the latter bearing, said bearing being supported in a iixed predetermined position when locked for use, a shaft received in said bearings for carrying the contact roll, said shaft projecting for a substantial distance outside the xed bearing, and a power operated actuator connected to the projecting end of said shaft, whereby on releasing the releasable bearing the actuator may tilt the free end of the contact roll in proper direction to facilitate changing the abrasive-belt thereon.

2. A belt grinder as deiined in claim 1, in which the releasable bearing and its bearing support have sloping or dovetail slots dimensioned to slidably receive mating gibs, and in which clamp means are provided for forcibly moving the gibs longitudinally into or out of the mating slots in order to anchor or release the bearing.

3. A belt grinder comprising a contact roll, a self-aligning bearing iixedly mounted at one end of said roll, a quickly releasable bearing at the other end of the roll, clamp means to lock or release the latter bearing,a shaft received in said bearings for carrying the contact roll, said shaft projecting for a substantial distance outside the fixed bearing, a main pulley on said shaft outside the fixed bearing, a driving motor beneath said shaft connected to said pulley by a belt, an idler roll spacedfrom the contact roll, and an actuator outside said pulley connected to a bearing on the projecting end of said shaft, whereby on releasing the releasable bearing the actuator may tilt the free end of the contact roll to facilitate changing the abrasive belt thereon, the direction of the actuator and motor belt being so related to the idler that the abrasive belt and motor belt are simultaneously loosened by the motion of the actuator.

4. A belt rgrinder as defined in claim 3, having additional mechanism for oscillating the contact roll shaft a small amount in axial direction, said means including a bracket secured to the self-aligning bearing for movement therewith, a speed reducing means carried by said bracket and driven by the contact roll shaft, an eccentric driven at reduced speed by said speed reducing means and disposed on said bracket on an axis transverse to the shaft outside the end of the shaft, a connecting link between said eccentric and a bearing on said shaft for oscillating the shaft, said bracket and oscillating mechanism tilting` with the shaft and contact roll when the latter are tilted by the actuator for changing the abrasive belt.

5. A belt grinder comprising a contact roll, a tiltable i and driven by the contact roll shaft, an eccentric driven at reduced speed by said reducing means, a connecting link between said eccentric and a bearing on said shaft for Yoscillating the shaft, said bracket and oscillating mechanism tilting with the shaft and contact roll when the latter are tilted by the actuator for changing the abrasive belt.

7. A belt grinder comprising a contact roll, a tiltable bearing iixedly mounted at one end of said roll, a quickly releasable bearing at the other end of the roll, clamp means to lock or release the latter bearing, a shaft received in said bearings for carrying the contact roll, said shaft projecting for a substantial distance outside the iixed bearing, an accurately adjustable pressure roll disposed immediately in front of the contact roll, an idler roll spacedV rearward a substantial distance from the Contact roll for tensioning the abrasivebelt, and a generally upright but somewhat angularly disposed actuator connected to a bearing on the projecting end-of the shaft, the slope of the actuator being such that on freeing the releasable bearing, the freed end of the contact roll is moved upward and 'rearward away from the pressure roll and toward the idler roll, thereby facilitating changing the abrasive belt.

8. A belt grinder as defined in claim 7, in'which the releasable bearing and its bearing support have sloping or dovetail slots dimensioned to slidably receive mating gibs, one of said gibs being straight and the other being tapered, and in which clamp means are provided for forcibly moving th gibs longitudinally into or out of the mating slots in order to anchor or release the bearing.

9. A belt grinder comprising a contact roll, a self-aligning bearing fixedly mounted at one end of said roll, a quickly releasable bearing at the other end of the roll, clamp means to lock or release the latter bearing, a shaft received in said bearings for carrying the contact roll, said shaft projecting for a substantial distance outside the fixed bearing, a main Vpulley on said shaft outside the fixed bearing, a driving motor beneath said shaft connected to said pulley by a generally upright belt, an accurately adjustable pressure roll disposed immediately in front of the contact roll, an idler roll spaced rearward a substantial distance from the contact roll for tensioning the abrasive belt, and agenerally upright but somewhat angularly disposed actuator outside the main drive pulleyand connected to a bearing on the projecting end of the shaft, the slope of the actuator being such that on freeing the releasable bearing, the freed end of the contact roll is moved upward and rearward away from the pressure roll and toward the idler roll, thereby facilitating changing the abrasive belt. f

10. A belt grinder as defined in claim 9, having additional mechanism for oscillating the contact roll shaft a small amount in axial direction, said means including a bracket secured to the self-aligning bearing for movement therewith, a speed reducing means carried by said bracket and driven by the contact roll shaft, an eccentric driven at reduced speed by said speed reducing means and disposed on said bracket on an axis transverse to the shaft outside the end of the shaft, a connecting link between said eccentric and a bearing on said shaft for oscillating the shaft, said bracket and oscillating mechanism tilting with the shaft and contact roll when the latter are tilted by the actuator for changing the abrasive belt.

1l. A belt grinder for accurately grinding wide sheet material toa desired thickness, said grinder comprising a contact roll, an idler roll spaced a substantial distance rearward of the contact roll for tensioning an abrasive belt on said rolls, an accurately adjustable pressure roll in front of the contact roll, precision means for precisely adjusting the spacing between the pressure roll and the contact roll, a motor and main drive for driving the shaft of the contact roll, and means also driven by said motor for oscillating the contact roll a very short distance in axial direction, said means comprising a speed reducing means, an eccentric driven at reduced speed from said speed reducing means, and a connecting link from said eccentric to said contact roll shaft to reciprocate the same.

l2. A belt grinder comprising a contact roll, an idler roll spaced a substantial distance rearward of the contact roll for tensioning an abrasive belt on said rolls, an accurately adjustable pressure roll in front of the contact roll, a motor and main drive for driving the shaft of the contact roll, and means also driven by said motor for oscillating the contact roll a very short distance in axial direction, said means comprising a speed reducing gear box, a drive from the contact roll shaft to said gear box, an eccentric driven at reduced speed from said gear box on an axis transverse to that of the contact roll and outside the end of the contact roll shaft, and a connecting link from said eccentric to a bearing on said contact roll shaft to reciprocate the same.

13. A belt grinder comprising a contact roll, means to drive the same rotatably at high speed, additional power driven means to oscillate the same a short distance at a slower speed in axial direction in order to move the belt from side to side, an idler roll disposed a substantial distance in back of the contact roll for tensioning an abrasive belt carried by said rolls, bearings at the ends of said idler roll, and means at said bearings to accommodate axial movement of the idler roll to help the latter follow the side-to-side movement of the belt resulting from the aforesaid power driven axial movement of the contact roll.

14. A belt grinder comprising a contact roll, means to drive the same rotatably, additional means to oscillate the same a short amount at slower speed in axial direction, an idler roll disposed a substantial distance in back of the contact roll for tensioning an abrasive belt carried by said rolls, bearings at the ends of said idler roll, and means at said bearings to accommodate axial movement of the idler roll to help the latter follow the axial movement of the contact roll, said means comprising cylindrical bearings to take the main radial thrust while affording axial movement, compression springs which tend to center the idler roll, thrust bearings receiving the thrust of said springs, and means to adjust the tension of the compression springs and to thereby adjust the freedom of axial movement of the idler roll.

15. A belt grinder comprising a contact roll, a shaft carrying the same, a tiltable bearing iixed at one end, said shaft extending outside said bearing, another bearing releasably mounted at the other end, an idler roll spaced a substantial distance in back of the contact roll, a shaft carrying the idler roll, bearings for said shaft, a yoke carrying said bearings and located in front of the idler roll between the top and bottom Vspans of the abrasive belt, means urging said yoke rearward to tension the belt, an overhung beam carrying said means at the side of the machine having the fixed bearing, tracking means at the latter' side of the machine for detecting excessive lateral movement of the belt, means automatically moved in response to said tracking means for tilting the yoke to restore proper belt position, the overhung mounting of the bearing yoke and the releasable bearing of the contact roll facilitating changing the abrasive belt, and an actuator for tilting the contact roll located and acting on said contact roll shaft outside the ixed bearing, said actuator on release of the releasable bearing serving to tilt the contact roll upward and rearward toward the idler roll to facilitate the belt changing operation.

16. A belt grinder comprising a contact roll, a shaft carrying the same, a tiltable bearing fixed at one end, said shaft extending outside said bearing, another bearing releasably mounted at the other end, an idler roll spaced a substantial distance in back of the contact roll, a shaft carrying the idler roll, bearings for said shaft, a yoke carrying said bearings and located in front of the idler roll between the top and bottom spans of the abrasive belt, means urging said yoke rearward to tension the belt, an overhung beam carrying said means at the side of the machine having the fixed bearing, tracking means at the latter side of the machine for detecting excessive lateral movement of the belt, means automatically moved in response to said tracking means for tilting the adjacent end of the yoke upward or downward to restore proper belt position, the overhung mounting of the bearing yoke and the releasable bearing of the contact roll facilitating changing the abrasive belt, driving means for the contact roll located outside the iixed bearing, and an actuator for tilting the contact roll located and acting on said contact roll shaft outside the driving means, said actuator on release of the releasable bearing serving to tilt the contact roll upward and rearward toward the idler roll to facilitate the belt changing operation.

17. A belt grinder comprising a contact roll, a shaft carrying the same, a tiltable bearing fixed at one end, said shaft extending outside said bearing, another bearing releasably mounted at the other end, an idler roll spaced a substantial distance in back of the contact roll, a shaft carrying the idler roll, bearings for said shaft, a yoke carrying said bearings and located in front of the idler roll between the top and bottom spans of the abrasive belt, means urging said yoke rearward to tension the belt, an overhung beam carrying said means at the side of the machine having the ixed bearing, tracking means at the latter side of the machine for detecting excessive lateral movement of the belt, means automatically moved in response to said tracking means for tilting the yoke to restore proper belt position, the overhung mounting of the bearing yoke and the releasable bearing of the contact roll facilitating changing the abrasive belt, an actuator for tilting the contact roll located and acting on said contact roll shaft outside the fixed bearing, and a bracket movable with the extension of the Contact roll shaft outside the fixed bearing, said bracket carrying means for oscillating the contact roll for a short distance in axial direction, said actuator on release of the releasable bearing serving to tilt the contact roll upward and rearward toward the idler roll to facilitate the belt changing operation.

18. A belt grinder comprising a contact roll, a shaft carrying the same, a tiltable bearing fixed at one end, said shaft extending outside said bearing, another bearing releasably mounted at the other end, an idler roll spaced a substantial distance in back of the contact roll, a shaft and bearings carrying the idler roll, a yoke carrying said shaft and bearings and located in front of the idler roll between the top and bottom spans of the abrasive belt, means urging said yoke rearward to tension the belt, an overhung beam carrying said means at the side of the machine having the fixed bearing, the bearings carried by said yoke affording a limited side to side or axial movement of the idler roll, tracking means at the latter side of the machine for detecting excessive lateral movement of the belt, means automatically moved in response to said tracking means for tilting the adjacent end of the yoke upward or downward to restore proper belt position, the overhung mounting of the bearing yoke and the releasable bearing of the contact roll facilitating chang-` ing the abrasive belt, driving means for the Ycontact roll located outside the fixed bearing, an actuator for tilting the contact roll located and acting on said contact roll shaft outside the driving means, and a bracket movable with the extension of the contact roll shaft outside the fixed bearing, said bracket carrying means for oscillating the contact roll for a short distance in axial direction, said actuator on release of the releasable bearing serving to tilt the contact roll upward and rearward toward theV idler roll to facilitate the belt changing operation.

19. A belt grinder comprising a contact roll, an idler` roll spaced a substantial distance in back of the contact roll, power driven means to rotate the contact roll at high speed andV to oscillate the contact roll a short distance in axial direction at a slower speed in order to move the belt from side to side, a shaft and bearings carrying the idler roll, a tiltable yoke carrying said shaft and bearings, said bearings affording a limited axial movement of the idler roll corresponding to the aforesaid intentionally caused side-to-side movement of the belt, tracking means for detecting excessive lateral movement of the belt, and means automatically moved in response to said tracking means for tilting the yoke in order to restore properbelt position.

20. A belt grinder comprising a contact roll, a shaft carrying the same, a bearing fixed at one end, an idler roll spaced a substantial distance in back of the contact roll, a shaft -and bearings carrying the idler roll, a yoke carrying said shaft and bearings and located in front of theV idler roll between the top and bottom spans of the.

abrasive belt, means urging said yoke rearward to tension the belt, an overhung beam carrying said means at the side of the machine having the fixed bearing, the bearings carried by said yoke affording a limited side to side or axial movement of the idler roll, the overhung mounting of the bearing yoke facilitating changing the abrasive belt, driving means for the contact roll, and means for oscillating the contact roll for a short distance in axial direction.

21. A belt grinder comprising a contact roll, a shaft carrying the same, a bearing fixed at one end, an idler roll spaced a substantial distance in back of the contact roll, a shaft and bearings carrying the idler roll, a yoke carrying said shaft and bearings and located in front of theidler roll between the top and bottom spans of the abrasive belt, means urging said yoke rearward to tension the belt, an overhung beam carrying said means at the side of thermachine having the fixed shaft and bearing, the shaft and bearings carried by said yokeraffording a limited floating side to side or axial movement of the idler roll, tracking means at the latter side of the machine for detecting excessive lateral movement of the belt,V

means automatically moved in response to said tracking means for tilting the adjacent end of the yoke upward or downward to restore proper belt position, the overhung mounting of the bearing yoke facilitating changing the abrasive belt, driving means for the contact roll, and means for oscillating the Contact roll for a short distance in axial direction.

22. A belt grinder comprising a contact roll, a shaft carrying the same, a bearing fixed at one end, another bearing releasably mounted at the other end, an idler roll spaced a substantial distance in back of the contact roll, a shaft and bearings carrying the idler roll, aV yoke carrying said shaft and bearings and located in front of the idler roll between the top and bottom spans of the abrasive belt, means urging said yoke rearward to tension the belt, an overhung beam carrying said means at the side of the machine having the fixed bearing, the shaft andy bearings carried by said yoke affording a limited side to side or axial movement of the idler roll, the overhung mounting of the bearing yoke and the releasable bearing of the contact roll facilitating changing' the abrasive belt, driving means for the contact roll, and means for oscillating the contact roll for a short distance inY roll, a shaft and bearings carrying the idler roll, a yoke r carrying said shaft, and bearings and located in front of the idler roll between the top and bottom spans of the abrasive belt, means urging said yoke rearward to tension the belt, an overhung beam carrying said means at the side of the machine having the fixed bearing, the shaft and bearings carried by said yoke affording a limited side to side or axial movement of the idler roll, tracking means at the latter side of the machine for detecting excessive lateral movement of the belt, means automatically moved in response to said tracking means for tilting the adjacent end of the yoke upward or downward to restore proper belt position, the overhung mounting of the bearing yoke and the releasable bearing of the contact roll facilitating changing the abrasive belt, driving means for the contact roll, and means for oscillating the contact'roll for a short distance in axial direction.

24. A belt grinder comprising a contact roll, a shaft carrying the same, a fixed bearing for said shaft, an idler roll spacedV a substantial distance in back of the Contact roll, a shaft and bearings carrying the idler roll, a yoke carrying'said shaft and bearings and located vin front of the idler roll between the top and bottom spans of the abrasive belt when the belt is on saidV rolls, means urging said yoke rearward to tension the belt, an overhung beam carrying'said means at the side of the machine having the fixed bearings, tracking means at the latter side of the machine for detecting excessive lateral movement of the belt, the shaft and bearings carried by said yoke affording a limited side to side or axial movement of the idler'roll, and means automatically moved in response to said tracking means fortilting the yoke to restore proper belt position, the overhang mounting of the bearing yoke facilitating changing the abrasive belt.

25. A belt grinder for accurately grinding wide sheet material to a desired thickness, said grinder comprising a contact roll, atiltable bearing fixedly mounted at one end of said roll, a quickly releasable bearing Vat the other end of the roll, means including a movable Wedge block and a lever for moving the same to lock or release the latter bearing, said bearing being supported in a fixed predetermined position when locked for use, a shaft received in said bearings for carrying the contact roll, and a power operated actuator so releated to said shaft that on releasing the releasable bearing the actuator may tilt the free end of the contact roll in proper direction to facilitate changing the abrasive'belt thereon.

26. A coated abrasive belt machine comprising a frame; a contact roll and an idler roll mounted for rotation within said frame; a coated abrasive belt trained centrally over said rolls; means to position said rolls so that said abrasive belt may be trained thereover and removed therefrom; oscillating means associated with one of said rolls to oscillate such roll transverse to the direction of travel of said belt; bearing means supporting the other of said rolls to float said other roll and to permit axial oscillation of said other roll within said bearing means when an oscillating force is transmitted to said other roll through said abrasive belt; and means to maintain said coated abrasive belt centered on said idler and contact rolls.

27. A belt grinder comprising a contact roll, a pressure roll, a tiltable bearing xedly mounted at one end of said contact roll, a shaft received in said bearing for carrying the contact roll, said shaft projecting for a substantial distance outside the tiltable bearing, an actuator connected to the projecting end of said shaft for moving the same in a direction transverse to the axisof the shaft, whereby the actuator may tilt the free end of the contact roll away from the pressure roll in order to facilitate changing the abrasive belt thereon, a bracket secured to the tiltable bearing for movement therewith, and power driven means carried by said bracket for oscillating the contact roll shaft for a short distance in axial direction, said bracket and oscillation-causing means tilting with the shaft and Contact roll when the latter are tilted by the actuator for Changing the abrasive belt.

28. A belt grinder comprising a contact roll, a pressure roll, a tiltable bearing xedly mounted at one end of said contact roll, a shaft received in said bearing for carrying the contact roll, said shaft projecting for a substantial distance outside the tiltable bearing, an actuator connected to the projecting end of said shaft for moving the same in a direction transverse to the axis of the shaft, whereby the actuator may tilt the free end of the contact roll away from the pressure roll in order to facilitate changing the abrasive belt thereon, and additional means for oscillating the c ontact roll shaft a small amount in axial direction, said means including a bracket secured to the tiltable bearing for movement therewith, a speed reducing means carried by said bracket and driven by the contact roll shaft, an eccentric driven at reduced speed by said reducing means, and a connecting link between said eccentric and'a bearing on said shaft for oscillating the shaft, said bracket and oscillating mechanism tilting with the shaft and contact roll when the latter are tilted by the actuator for changing the abrasive belt.

29. A coated abrasive belt machine comprising a frame, a contact roll and an idler roll mounted for rotation within said frame, a coated abrasive belt trained centrally over said rolls, means to position said rolls so that said abrasive belt may be trained thereover and removed therefrom, oscillating means associated with one of said rolls to oscillate such rst roll transverse to the direction of travel of said belt, bearing means supporting the second of said rolls to float said second roll and to permit axial oscillation of said second roll within said bearing means when an oscillating force is transmitted to said second roll through said abrasive belt, means to maintain said coated abrasive belt centered on said idler and contact rolls, and compression springs at the ends of the second roll for tending to normally center the second roll.

30. A coated abrasive belt machine comprising a frame, a contact roll and an idler roll mounted for rotation within said frame, a coated abrasive belt trained centrally over said rolls, means to position said rolls so that said abrasive belt may be trained thereover and removed therefrom, oscillating means associated with one of said rolls to oscillate such first roll transverse to the direction of travel of said belt, bearing means supporting the second of said rolls to float said second roll and to permit axial oscillation of said second roll within said bearing means when an oscillating force is transmitted to said second roll through said abrasive belt, means to maintain said coated abrasive belt centered on said idler and contact rolls, compression springs at the ends of the second roll for tending to normally center the second roll, and additional means to adjust the force exerted by said centering springs.

31. A belt grinder comprising a contact roll, a shaft carrying the same, a bearing xed at one end, an idler roll spaced a substantial distance in back of the contact roll, a shaft and bearings carrying the idler roll, a yoke carrying said shaft and bearings and located in front of the idler roll between the top and bottom spans of the abrasive belt, means urging said yoke rearward to tension the belt, an overhung beam carrying said means at the side of the machine having the xed bearing, the shaft and bearings carried by said yoke affording a limited floating side to side or axial movement of the idler roll, tracking means at the latter side of the machine for detecting excessive lateral movement of the belt, means automatically moved in response to said tracking means for tilting the adjacent end of the yoke upward or downward to restore proper belt position, the overhung mounting of the bearing yoke facilitating changing the abrasive belt, driving means for the contact roll, means for oscillating the contact roll for a short distance in axial direction, and compression springs at the ends of the idler roll tending to center the idler roll.

32. A belt grinder comprising a contact roll, a shaft carrying the same, a bearing xed at one end, anV idler roll spaced a substantial distance in back of the contact roll, a shaft and bearings carrying the idler roll, a yoke carrying said shaft and bearings and located in front of the idler roll between the top and bottom spans of the abrasive belt, means urging said yoke rearward to tension the belt, an overhung beam carrying said means at the side of the machine having the fixed bearing, the shaft and bearings carried by said yoke affording a limited fioating side to side or axial movement of the idler roll, tracking means at the latter side of the machine for detecting excessive lateral movement of the belt, means automatically moved in response to said tracking means for tilting the adjacent end of the yoke upward or downward to restore proper belt position, the overhung mounting of the bearing yoke facilitating changing the abrasive belt, driving means for the contact roll, means for oscillating the con'- tact roll for a short distance in axial direction, compression springs at the ends of the idler roll tending to center the idler roll, and additional means to adjust the force exerted by said centering springs.

33. A belt grinder for accurately grinding wide sheet material -to a desired thickness, said grinder comprising a contact roll, a tiltable bearing iixedly mounted at one end of said roll, a quickly releasable bearing at the other end of the roll, means to lock or release the latter bearing, said bearing being supported in a fixed predetermined position when locked for use, a shaft received in said bearings for carrying the contact roll, a pressure roll disposed immediately adjacent the contact roll, precision means for precisely adjusting the spacing between the pressure roll and the contact roll, an idler roll spaced a substantial distance from the contact roll for tensioning the abrasive belt, said idler roll being overhung on bearing means supported from the same side of the grinder as the tiltable bearing, a power operated actuator so related to said Contact roll shaft that on releasing the releasable bearing the actuator serves to tilt the free end of the contact roll away from the pressure roll and toward the idler roll, thereby facilitating changing the abrasive belt, power driven means operatively connected to the said contact roll shaft to cause axial reciprocation of the same, and means affording a limited floating axial movement of the idler roll relative to the idler roll bearings in order to follow the reciprocation of the contact roll.

34. A belt grinder for accurately grinding wide sheet material to a desired thickness, said grinder comprising a contact roll, a tiltable bearing xedly mounted at one end of said roll, a quickly releasable bearing at the other end of the roll, means to lock or release the latter bearing, said bearing being supported in a xed predetermined position when locked for use, a shaft received in said bearings for carrying the Contact roll, a pressure roll disposed immediately adjacent the contact roll, precision means for precisely adjusting the spacing between the pressure roll and the contact roll, an idler roll spaced a substantial distance from the contact roll for tensioning the abrasive belt, said idler roll being overhung on bearing means supported from the same side of the grinder as the tiltable bearing, a power operated actuator so related to said contact roll shaft that on releasing the releasable bearing the actuator serves to tilt the free end of the contact roll away from the pressure roll and toward the idler roll, thereby facilitating changing the abrasive belt, power driven means operatively connected to the said contact roll shaft to cause axial reciprocation of the same, means affording a limited floating axial movement of the idler roll relative to the idler roll bearings in order to follow the reciprocation of the contact roll, and compression springs at the ends of the idler roll for tending to normally center the idler roll.

35. A coated abrasive belt machine comprising a frame, a contact roll and an idler roll mounted for rotation within said frame, a coated abrasive belt trained centrally over said rolls, means to position said rolls so that said abrasive belt may be trained thereover and removed therefrom, bearing means supporting said idler roll for tloating axial movement Within said bearing means, oscillating means associated with said Contact roll to oscillate said roll transverse to the direction of travel of said belt and through said belt to oscillate said idler roll in an axial direction, means to drive said Contact roll and said oscillating means, and means to maintain said coated abrasive belt centered on said idler and contact rolls.

36. In a coated abrasive belt machine having a frame and an idler roll and a contact roll mounted for rotation within said frame and adapted to support and drive a coated abrasive belt replaceably trained over said rolls, said contact roll being mechanically driven and oscillated, mounting means for said idler roll comprising a shaft for supporting said idler roll, a pair of bearings one at each end of said shaft adapted to permit saidshaft to rotate andV to move'axially Within said bearings, a yoke adapted it to support said bearings free of contact with said frame, said yoke being secured to said frame, spring-loaded means adjacent each end of said shaft exterior of said bearings whereby said shaft may oscillate when an oscillating force is transmitted to said roll through an abrasive belt trained over said idler roll andl said driving oscillating contact roll, and means to move said idler roll relative to said contact roll to tension an abrasive belt when trained thereover.

References Cited in the le of this patent` UNITED STATES PATENTS 781,423 Hemming Ian. 31, 1905 2,274,268 Hercik Feb. 24, 1942 2,340,121 Hamilton Ian. 25, 1944 2,597,256 Murray May 20, 1952 2,640,304 McEwan a June 2, 1953 

13. A BELT GRINDER COMPRISING A CONTACT ROLL, MEANS TO DRIVE THE SAME ROTATABLY AT HIGH SPEED, ADDITIONAL POWER DRIVEN MEANS TO OSCILLATE THE SAME A SHORT DISTANCE AT A SLOWER SPEED IN AXIAL DIRECTION IN ORDER TO MOVE THE BELT FROM SIDE TO SIDE, AN IDLER ROLL DISPOSED A SUBSTANTIAL DISTANCE IN BACK OF THE CONTACT ROLL FOR TENSIONING AN ABRASIVE BELT CARRIED BY SAID ROLLS, BEARINGS AT THE ENDS OF SAID IDLER ROLL, AND MEANS AT SAID BEARINGS TO ACCOMMODATE AXIAL MOVEMENT OF THE IDLER ROLL TO HELP THE LATTER FOLLOW THE SIDE-TO-SIDE MOVEMENT OF THE BELT RESULTING FROM THE AFORESAID POWER DRIVEN AXIAL MOVEMENT OF THE CONTACT ROLL. 